Pile articles (20,22), especially pile weatherstripping, and a method and apparatus (10) for making such articles where the backing (24) and the pile (26) are of unlike material, especially nylon yarn for the pile (26) and polypropylene containing material for the backing (24), wherein prior to the welding of the pile (26) to the backing (24) the pile is first pre-heated using ultrasonic energy to melt the pile in a region (65) thereof where the pile is ultrasonically welded to the backing and before the weld is made. The ultrasonic melting occurs upstream of the location where the pile (26) is welded to the backing (24) so that the ultrasonically pre-heated melted region (65) of the pile (26) can cool and become at least partially solidified. Then pile (26) at the pre-heated melted region (65) is welded to the backing (24) and causes a reactive or chemical weld to occur, thereby attaching the pile (26) to the backing (24).